I think the real takeaway here is that any part of your underlying technology that you don't thoroughly understand puts you at risk, and that risk goes up significantly in a large volume environment. It's frequently not possible to have experts on-hand for everything, but you need to make sure you have them for your critical stuff. They don't necessarily have to be on your payroll either; really good consulting companies can do a lot for you as well. (Disclosure: I'm a partner at a consulting company).

When it comes to Postgres and data, I'll just say what I've been saying for ~20 years:

"All databases suck, each one just sucks differently."